Over-the-wing passenger boarding bridges for servicing aircraft doorways located above or behind the wing are known in the art (U.S. Pat. No. 6,496,996, DE 10046010, WO 0009395, U.S. Pat. Nos. 3,538,529, 3,722,017). Each prior art solution provides a tunnel section that is supported in a cantilever-like fashion by an overhead support system, such that the tunnel section is positionable over the wing of the aircraft for engaging a rear doorway that is located behind the wing. To this end, the tunnel section typically includes at least a telescopic portion including a cab mounted at an outboard end thereof, the cab for being aligned with the rear doorway. Unfortunately, the length of the tunnel section that must be supported often is considerable, especially for bridges that are designed to engage a rear doorway of a larger aircraft or of a “stretch” model of some smaller types of aircraft. Of course, an overhead adjustable support system must be capable not only of supporting the entire weight of the tunnel section, but also the weight of passengers moving through the tunnel section, the weight of service equipment mounted to the tunnel section, and the weight of snow and ice accumulated on external surfaces of the tunnel section. Furthermore, the overhead adjustable support system must maintain the tunnel section approximately stationary during use, so as to avoid jostling passengers or allowing the tunnel section to collide with a surface of the aircraft. Further still, the overhead adjustable support system must be capable of moving precisely the tunnel section to a desired stopping position when the tunnel section is being aligned with the rear doorway of the aircraft.
In U.S. Pat. No. 6,496,996, issued to Worpenberg and Scharf on Dec. 24, 2002, an overhead adjustable support system is provided including a frame which surrounds the tunnel section and which is pivotably mounted to a massive post that is permanently secured to the apron. An extension arm is rigidly or moveably fastened to the frame, and the telescoping tunnel elements of the tunnel section are suspended in a height-adjustable manner from the extension arm. It is a limitation of the system that is disclosed in U.S. Pat. No. 6,496,996 that the extension arm requires a massive counterweight, which could at times be positioned above portions of the passenger boarding bridge, as well as massive lift cylinders in order to support the tunnel section in the height adjustable manner. Accordingly, the system is expensive to implement, provides limited flexibility and requires construction of permanent support structures on the apron surface for supporting the frame.
In DE 10046010, disclosed is an over-the-wing bridge including a telescoping tunnel section that is pivotally mounted to an outboard end of a radial bridge. An overhead adjustable support system is provided including an elaborate assembly of support rods, which is disposed both above and below portions of the telescoping tunnel section and the radial bridge, for supporting the telescoping tunnel section in a height adjustable manner. To this end, lift columns are provided for adjusting the level of the telescoping tunnel section relative to that of the radial bridge. In fact, the support system for the telescoping tunnel section appears to be an extension of a main elevating member of the radial bridge. The system described in DE 10046010 not only is awkward and expensive, but also appears to support only limited vertical adjustment of the outboard end of the telescoping tunnel section. Furthermore, horizontal adjustment of the outboard end of the telescoping tunnel section appears to be severely limited as a result of some of the support rods extending between the main elevating member of the radial bridge.
In WO 0009395, an overhead adjustable support system is provided in the form of a massive, horizontally pivotal extension arm which is mounted on a support. An opposite end of the extension arm carries a counterweight, which could at times be positioned above portions of the passenger boarding bridge. Unfortunately, the sheer size of the extension arm necessitates the construction of an equally massive support, including plural support posts surrounding the passenger boarding bridge and permanently secured to the apron. Accordingly, the system that is disclosed in WO0009395 is both expensive and awkward.
U.S. Pat. No. 3,538,529 issued to Breier on Nov. 10, 1970 discloses an overhead supported aircraft boarding bridge, including a slightly arched telescoping tunnel section, which may be cantilevered over the wing of an aircraft for servicing a rear doorway thereof. The entire telescoping tunnel section is pivotally connected to a static structure, thereby providing limited freedom of vertical motion for clearing the wing and mating to the rear doorway of the aircraft. In particular, the overhead supported boarding bridge is supported by a cantilevered structure which extends out from the static structure to support a track which extends above and generally transversely or arcuately to the tunnel section of the bridge. A carriage rides on the track and supports the tunnel section by vertically extensible supports. Operation of the carriage along the track effects horizontal swinging of the tunnel section about its pivoted inner end and actuation of the vertically extensible supports effects vertical swinging of the tunnel section. Unfortunately, this system is complicated, provides limited flexibility and is expensive.
U.S. Pat. No. 3,722,017 issued to Gacs et al. on Mar. 27, 1973 discloses an over-the-wing aircraft boarding bridge having a main passageway member pivotally supported at the terminal building end on a track mounted rack propelled carriage. The main passageway member is elevatable and depressable so that its outer end portion, slightly arched, may extend over the wing of an aircraft. At its outer end the main passageway mounts a lateral passageway including an operator's cab, which is for being mated to a rear doorway of the aircraft. The lateral passageway appears to serve as a bridge between the rear doorway and the main passageway element, which passageway lacks sufficient freedom of vertical movement to engage the rear doorway directly. This system also is complicated, provides limited flexibility and is expensive.
None of the prior art solutions provides a desirable balance between safety concerns, simplicity of construction, ease of operation and flexibility to service aircraft of different types. It would therefore be advantageous to provide an overhead adjustable support system for use with a passenger boarding bridge. It would be particularly advantageous to provide an overhead adjustable support system for use with an over-the-wing passenger boarding bridge that overcomes the above-mentioned disadvantages associated with the prior art.